Logo
Builders' Plan Gallery  |  Hip Pocket Web Site  |  Contact Forum Admin  |  Contact Global Moderator
November 17, 2019, 10:13:37 AM *
Welcome, Guest. Please login or register.
Did you miss your activation email?

Login with email, password and session length
 
Home Help Search Login Register
Pages: [1] 2 3 4 5 6 7 8 ... 16   Go Down
Print
Author Topic: Bungee Launch 36" Gliders  (Read 35587 times)
0 Members and 1 Guest are viewing this topic.
PeeTee
Titanium Member
*******

Kudos: 48
Offline Offline

United Kingdom United Kingdom

Posts: 2,251

Topic starter


Ignore
« on: March 20, 2013, 06:13:39 PM »

Jon (Yak52) started a topic on bungee launch aerodynamics. The UK SAM organisations have just agreed the rules for 36" bungee launch gliders for vintage and classic models, and this allows scaling.

Awhile ago I picked up a plan for a quirky French beginners glider, the CB 34, V dihedral, profile wing and twin fins - luvverly Cheesy. It's of mid 40s vintage, 1m span which I reduced to 36". The profile fuselage is easily made, as are the wings and tail. I'm fitting a Tomy timer for DT, and this is how far I've got at present - ready for a comp over Easter......
Sorry about the rotten photos!

Peter
Attached files Thumbnail(s):
Bungee Launch 36" Gliders
Bungee Launch 36" Gliders
Bungee Launch 36" Gliders
Logged
FreeFlightModeller
Russ Lister
Titanium Member
*******

Kudos: 68
Online Online

United Kingdom United Kingdom

Posts: 3,883


Russ Lister



Ignore
« Reply #1 on: March 20, 2013, 06:44:44 PM »

Good news that the class has been more widely accepted ... I'll have to start thinking about a model that will suit both the SAM and Peterborough events.

Will be following your progress Peter  Smiley
Logged
PeeTee
Titanium Member
*******

Kudos: 48
Offline Offline

United Kingdom United Kingdom

Posts: 2,251

Topic starter


Ignore
« Reply #2 on: March 20, 2013, 06:54:35 PM »

Russ

Thanks. Bungee launch has been around for many years - I watched the Bournemouth club run a bungee launch comp for Skyleada 3 Footers the best part of 10 years ago, but the Peterboro' club has done a good job of publicising it. I'm not averse to trundling across the ground with a towline glider, but what I've seen of bungee launch makes it look fun, and good for smaller (windier) sites.

If you get down to MW over Easter, all things being equal I'll have the model ready Roll Eyes

Either way, I look forward to seeing you there.

Cheers

Peter
ps keep up the good work with the scale builds!
Logged
DaddyO
Platinum Member
******

Kudos: 61
Offline Offline

United Kingdom United Kingdom

Posts: 1,448




Ignore
« Reply #3 on: March 21, 2013, 04:32:11 AM »

Ahah!

Now I see why you were rummaging through all those glider plans Mon Ami Mate  Wink

Nice choice of model; typical Gallic style with the twin fins. Any trade secrets you are going to give away about hooks? (I understand that they are angled more than normal and possibly further back?

Hopefully will have sorted out some vehicular transport by then so may pop along to MW to see them in action . . .
Toodlepip
Paul
Logged

There cannot be a crisis today, my schedule is already full
Yak 52
Titanium Member
*******

Kudos: 67
Offline Offline

United Kingdom United Kingdom

Posts: 2,483


Free Flight Vagrant



Ignore
« Reply #4 on: March 21, 2013, 07:59:42 AM »

Looks good Peter. I've been building a Lulu Baby scaled up to 36".

Jon
Logged
lincoln
Titanium Member
*******

Kudos: 32
Offline Offline

United States United States

Posts: 2,056



Ignore
« Reply #5 on: March 21, 2013, 06:46:54 PM »

That DOES look like a nice project.

If you like CB designs, and you're ambitious, how about a scaled down CB28?:
http://lesgpr.free.fr/construire/cb28/cb28-2.jpg

More CB stuff:
http://clap54b.free.fr/vollibre/musee/musee.htm

More interesting gliders, some even small enough:
http://claudel.dopp.free.fr/Les_planeurs/Aeromodeles_antiques/Planeurs-antiques.htm#x02_dm
http://www.sam78.cz/apr_list/samlist.php?type=1&orderby=rok

Logged
PeeTee
Titanium Member
*******

Kudos: 48
Offline Offline

United Kingdom United Kingdom

Posts: 2,251

Topic starter


Ignore
« Reply #6 on: March 21, 2013, 08:09:39 PM »

Lincoln, you are a gent indeed to discover such a vast selection of quirky models - many thanks. I understood that the CB 34 was a mid 40s design, not as early as '41, so that's a useful bit of information. I shall spread the word about the websites you kindly identified.

Thanks also to Paul & Jon for kind words. I think I'm running out of time for the first comp over Easter, but I'll give it a go. Tonight I managed to put mylar on the fus and will cover with tissue tomorrow, and perhaps the tailplane as well. The major job is to join the wing panels in such a way that they won't clap hands on the first launch Sad I need to make up some suitable dihedral braces, and am starting to wish I'd chosen a model with just tip dihedral.............oh well, style over substance as they say Roll Eyes

Peter
Logged
craig h
Gold Member
*****

Kudos: 4
Offline Offline

United States United States

Posts: 271



Ignore
« Reply #7 on: March 22, 2013, 07:51:02 AM »

 Very interesting...may I ask what size rubber will you use for the launch and what length ? Being unable to run for a launch perhaps this is something I may pursue...I have always wanted to try tow line but being unable to run has not allowed me to try..this may be an answer.

   Thanks..Craig h
Any info will be helpful..
Logged
PeeTee
Titanium Member
*******

Kudos: 48
Offline Offline

United Kingdom United Kingdom

Posts: 2,251

Topic starter


Ignore
« Reply #8 on: March 22, 2013, 08:13:43 AM »

Craig

The models of this size I've seen launched use 1/8" or less. This kind of bungee launch isn't r/c style where the models accelerate quickly, instead the models tend to kite up (hopefully to the top of the line) with the rubber maintaining tension on the monofilament. The overall  line length is 30m (just under 100ft) with 12.5 metres of unstretched rubber, and the rest nylon monofilament. Of course this is the spec for a low key competition class and you can use whatever you want for sport flying. Here's what a seasoned flyer wrote about it in the SAM 1066 Clarion newsletter:

"Bungee launching, or Hi-start as the Americans call it, has many attractions as those who have tried it will affirm. To see a model sailing high and handsome at the top of the launch and then neatly casting itself off into its flight pattern is a great joy.
But remember, this is not catapult launching. In fact, if you use a bungee as a catapult the model in all probability just ping off the line in a couple of seconds. Surprising little power is required to waft a glider aloft in, ideally, a normal glider-towing breeze – hence the specification of 1/8in rubber."

I hope this is of some interest.

Peter
Logged
ctelehany
Copper Member
**

Kudos: 0
Offline Offline

United States United States

Posts: 8



Ignore
« Reply #9 on: April 07, 2013, 07:28:49 PM »

Lots of good information on this thread.

I just finished building an Oly II with a 100" span.  I'd like to try this bungee launching technique so that a helper is not required for launching.  Would this be feasible?  Does anyone have a suggestion as to bungee and line lengths and diameters?

I'm not into contest performance. I'd just like to get enough altitude for a couple of minutes of gliding per launch.

Thanks.  Any help will be appreciated.
Logged
Pit
Palladium Member
********

Kudos: 129
Offline Offline

Germany Germany

Posts: 5,507


aka staubkorb


WWW

Ignore
« Reply #10 on: April 07, 2013, 08:42:59 PM »

The Oly, and other rc gliders NEED a high-start type of bungee (relative high-power).  A lightly built Oly (~4 pounds, max) might get by with a 6-7mm OD surgical tubing and 1mm nylon monofil - usually 15meter and 100meter.  A bit of a breeze is a good thing.  A better bet for rubber is the next size up - 8-10mm.

The Oly doesn't have ailerons so "kiting" on a weak bungee is asking for trouble if it falls off to the side (usually going inverted) with catastrophic results.
Logged

A Dedicated Convert to:
WWWoFF (Wonderfull Wacky World of Free Flight)

Comparing Spammers to a pile of organic waste is an insult to the organic waste!
applehoney
Titanium Member
*******

Kudos: 279
Offline Offline

Canada Canada

Posts: 3,162




Ignore
« Reply #11 on: April 08, 2013, 10:19:14 AM »

>A lightly built Oly (~4 pounds,

Lightly built Huh     Shocked

Interesting how things vary between categories and disciplines.
Logged
jswain
Silver Member
****

Kudos: 5
Offline Offline

United States United States

Posts: 153



Ignore
« Reply #12 on: April 08, 2013, 11:06:53 AM »

Lots of good information on this thread.I just finished building an Oly II with a 100" span.  I'd like to try this bungee launching technique so that a helper is not required for launching.  Would this be feasible?  Does anyone have a suggestion as to bungee and line lengths and diameters?I'm not into contest performance. I'd just like to get enough altitude for a couple of minutes of gliding per launch.Thanks.  Any help will be appreciated.

here is an all in one solution for your Oly2 => http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXYXK4&P=M.  If the field length available is less than the specs listed, feel free to cut the tubing and line dimensions in half for a shorter launch site.  I love my Oly2... Grin

john s.
Logged
JohnOSullivan
Silver Member
****

Kudos: 4
Offline Offline

Canada Canada

Posts: 203


WWW

Ignore
« Reply #13 on: April 08, 2013, 05:40:26 PM »

Seems to have seriously gone off topic.
The thread is for 36" gliders and is one that deserves serious consideration.
The Olly is an RC 100" glider which has little relevance in this thread.
Logged

John O'Sullivan
MAAC 5401
MACI 26
craig h
Gold Member
*****

Kudos: 4
Offline Offline

United States United States

Posts: 271



Ignore
« Reply #14 on: April 09, 2013, 10:51:05 AM »

Is it my understanding that the design of glider would have to be before the 1940's and wing span of 36".... no weight restrictions..covering used..and can be beefed up for strength?

  Thanks...Craig h

  This would be my first tow or bungee glider
Logged
Pit
Palladium Member
********

Kudos: 129
Offline Offline

Germany Germany

Posts: 5,507


aka staubkorb


WWW

Ignore
« Reply #15 on: April 09, 2013, 12:05:14 PM »

It's the UK SAM group that has set up a class.  Their cut-off dates for Classic and Vintage vary from those in the States from what I recall, so best to check with SAM-UK.
Logged

A Dedicated Convert to:
WWWoFF (Wonderfull Wacky World of Free Flight)

Comparing Spammers to a pile of organic waste is an insult to the organic waste!
ctelehany
Copper Member
**

Kudos: 0
Offline Offline

United States United States

Posts: 8



Ignore
« Reply #16 on: April 09, 2013, 01:00:23 PM »

Sorry to have veered off topic, but thanks for the help. I'm going to try JSWAIN's suggestion.

Logged
martynk
Bronze Member
***

Kudos: 1
Offline Offline

United Kingdom United Kingdom

Posts: 94


WWW

Ignore
« Reply #17 on: April 19, 2013, 11:18:12 AM »

Looks interesting. I was a little inspired when I saw the original Peterborough MAC proposal.
What is the technology?. Is there an autorudder?  if so how is it triggered? -  I suppose that DT will be conventional.

Regards

Martyn
Logged

--
Martyn
PeeTee
Titanium Member
*******

Kudos: 48
Offline Offline

United Kingdom United Kingdom

Posts: 2,251

Topic starter


Ignore
« Reply #18 on: April 19, 2013, 04:24:35 PM »

Martyn

Those who have flown off a bungee tell me that an autorudder probably isn't necessary. I've not finished my model so can't validate this. I do believe that a DT is necessary - a modified Tomy will do but needs a start activator when the model casts off from the line.

Peter
Logged
FreeFlightModeller
Russ Lister
Titanium Member
*******

Kudos: 68
Online Online

United Kingdom United Kingdom

Posts: 3,883


Russ Lister



Ignore
« Reply #19 on: April 19, 2013, 04:45:13 PM »

I used to do a lot of RC flying off bungee (over 35 years ago now  Shocked) .... it was more forgiving than I expected.
Looking forward to trying it out with a 36" glider  Smiley
Logged
skyrocket
Gold Member
*****

Kudos: 28
Offline Offline

United States United States

Posts: 672

nothing hard is ever easy



Ignore
« Reply #20 on: May 10, 2013, 02:45:55 PM »

Hi guys...just finished spraying everything and ready to start installing all the hardware...it's a Corsair that Peetee told me about..I didn't put a auto-rudder on so we'll see how that goes...pics coming up soon...I'm stoked to get it into the air next week at Geneseo's Hobo Meet, or if the weather looks bad for that weekend, sat my local contest field...
Logged
skyrocket
Gold Member
*****

Kudos: 28
Offline Offline

United States United States

Posts: 672

nothing hard is ever easy



Ignore
« Reply #21 on: June 25, 2013, 01:27:15 PM »

Tested the "Corsair" last week and it flew great. Didn't fit a auto-rudder yet and I'm not sure they need them. I didn't install a flag on the line either but will next time out as it was reluctant to release. BUT IT FLEW GREAT and with a little more trimming it should soar just fine. I decreased  the incidence by adding a 1/16" shim under the trailing edge and made a 1/16" wire tow hook as the aluminum one I cut out and installed didn't work smooth enough. For those of you who think 1/8" rudder isn't enough, you are in for a treat. I used 25 feet of 1/8" plus 75 feet of 50 lb. kite line attached to a 2 foot pole made from 1" dowel with a spike on the ground end and secured with a tent peg and 3 feet of  cord. Simple, easy to install and tons of fun (reminds me of a woman i once knew but that's another story). 
Logged
dputt7
Platinum Member
******

Kudos: 90
Offline Offline

Australia Australia

Posts: 1,986




Ignore
« Reply #22 on: June 26, 2013, 03:34:22 AM »

Pics please  Grin
Logged
skyrocket
Gold Member
*****

Kudos: 28
Offline Offline

United States United States

Posts: 672

nothing hard is ever easy



Ignore
« Reply #23 on: June 26, 2013, 03:27:59 PM »

Try these...
Attached files Thumbnail(s):
Re: Bungee Launch 36" Gliders
Re: Bungee Launch 36" Gliders
Logged
craig h
Gold Member
*****

Kudos: 4
Offline Offline

United States United States

Posts: 271



Ignore
« Reply #24 on: June 26, 2013, 10:51:41 PM »

Very nice glider !  Where did you find the plans....do you mind showing how you did your stake set up...looks like a lot of fun!

     Thanks for sharing
Logged
Pages: [1] 2 3 4 5 6 7 8 ... 16   Go Up
Print
Jump to:  

Powered by MySQL Powered by PHP Powered by SMF 1.1.21 | SMF © 2015, Simple Machines Valid XHTML 1.0! Valid CSS!